SB2020041910 - Improper Handling of Exceptional Conditions in xen (Alpine package)

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Main Vulnerability Database SB2020041910

SB2020041910 - Improper Handling of Exceptional Conditions in xen (Alpine package)

Published: April 19, 2020 Updated: October 19, 2022

Security Bulletin ID SB2020041910
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Adjecent network
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Handling of Exceptional Conditions (CVE-ID: CVE-2020-11743)

CWE-ID: CWE-755 - Improper Handling of Exceptional Conditions

CVSSv4: CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:U/U:Green


The vulnerability allows a remote user to perform a denial of service (DoS) attack.

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of a bad error path in GNTTABOP_map_grant. Grant table operations are expected to return 0 for success, and a negative number for errors. Some misplaced brackets cause one error path to return 1 instead of a negative value. The grant table code in Linux treats this condition as success, and proceeds with incorrectly initialised state. A buggy or malicious guest can construct its grant table in such a way that, when a backend domain tries to map a grant, it hits the incorrect error path. This will crash a Linux based dom0 or backend domain.


Remediation

Install update from vendor's website.

References